The present invention relates to the field of bicycles, and, in particular, concerns a bicycle pedal provided with a permanent magnet designed to interact with a sensor provided on the frame of the bicycle.
In recent years, there has been a constant increase in the use, on bicycles, of on-board computers associated with a display panel which supplies the cyclist with a set of data, for example the selected gear ratio or the speed of the bicycle. One of the parameters which is displayed from time to time, or which, at least, is used by the computer to calculate further parameters to be displayed, is the pedalling cadence. This parameter is measured by means of a sensor, for example a reed sensor fitted on the bicycle frame adjacent to a pedal crank and interacting with a permanent magnet fitted on the pedal, which activates the sensor whenever it passes in front of it.
According to the prior art, the aforesaid permanent magnet is fixed to the pedal crank by means of a connecting band or other means of connection which in all cases has an undesired bulk, interrupts the visual continuity of the pedal crank and does not provide complete security of the connection.
In order to overcome these disadvantages, the object of the invention is a bicycle pedal having a pedal shaft, characterized in that the shaft has an end surface in which a hole is formed, and in that a permanent magnet, designed to interact with a sensor provided on the frame of the bicycle, is positioned in the said hole.
It should be noted that the pedal shaft is conventionally provided with a hole, since this is used for the positioning on the lathe of the semi-finished piece from which the shaft is made.
According to the invention, this blind hole is used for the fitting of a permanent magnet, which is thus perfectly integrated in the pedal without any undesired bulk or unattractive appearance.
If the pedal shaft is made from ferromagnetic material, the aforesaid permanent magnet is retained within the aforesaid hole simply by magnetic attraction.
On the other hand, if the pedal shaft is made from a non-ferromagnetic material, for example titanium alloy, the permanent magnet can be fixed within the blind hole by any connecting means, but preferably it is held against an auxiliary element of ferromagnetic material which is secured within the hole, by being driven in for example.
Clearly, it is possible to provide for the sale of a kit of accessories for fitting an on-board computer and its accessories, including the pedalling cadence sensor, to a bicycle which initially does not have one. In this case, the aforesaid kit of accessories can be made to include a permanent magnet designed to be associated with the bicycle pedal and to interact with the aforesaid sensor provided on the frame, this magnet being shaped so that it can be housed within a hole provided on an end surface of the pedal shaft, as described above.